Mechanical actuation of downhole valves can be relatively difficult, owing to the difficulty in deploying shifting tools on coiled tubing, or conventional ball drop systems, for actuating such valves, especially in deviated wellbores. This is especially the case with respect to so-called “toe valves” or “toe sleeves”, which are disposed at, or close to, the furthest end of the wellbore. Toe valves are used to enable pressure dissipation, after pressure testing of a well and prior to completion, so that guns and/or balls may be pumped down.